Examoogle
ExamsTest SeriesCBATRank CheckPrevious Year PapersPassBook StoreMy BooksAI Tutor
ЁЯЫТ0
рдЕA
Examoogle

India's most trusted platform for competitive exam PDF books. Expert-authored, watermark-protected, instant access.

Exams & Practice
All Exams & SyllabusMock Test SeriesPrevious Year PapersPractice Questions (MCQs)Recruitment Notifications
Quick Links
Examoogle AI TutorExam NewsBook StoreMy BooksLogin / Sign Up
Support
About UsRefund PolicyPrivacy PolicyTerms of UseContact Us
┬й 2026 Examoogle. India's #1 competitive exam AI tutor.
ЁЯФТ SSL SecuredЁЯУ▒ UPI AcceptedЁЯз╛ GST Invoice
Examoogle

Join 60,000+ competitive exam aspirants

or with email
By continuing, you agree to ourTerms of Service&Privacy Policy
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Back to Practice Questions
CivilTransportation Engineering
PrevNext

The ideal form of curve for summit curve is

A

Lemniscate

B

Parabolic

C

Circular

D

Spiral

Correct Answer

тЪЩя╕П TE тАв Technical Concept & PrincipleCivilTransportation Engineering
Option B

Parabolic

Quick Summary:

The ideal form of a summit curve is a simple parabola because it provides a constant rate of change of grade, which ensures a smooth transition and consistent sight distance. This geometric profile allows for the uniform distribution of centrifugal force and provides the most comfortable vertical transition for vehicles traveling at high speeds.

тЪЩя╕ПTETechnical SolutionConcept & Principle
ЁЯТб Explanation

The ideal form of a summit curve is a simple parabola because it provides a constant rate of change of grade, which ensures a smooth transition and consistent sight distance. This geometric profile allows for the uniform distribution of centrifugal force and provides the most comfortable vertical transition for vehicles traveling at high speeds.

ЁЯФв Key Formulas

L=NS22(h1+h2)2L = \frac{NS┬▓}{2(\sqrt{h_1} + \sqrt{h_2})^2}L=2(h1тАЛтАЛ+h2тАЛтАЛ)2NS2тАЛ тАФ Length of summit curve for OSD

L=NS24.4L = \frac{NS┬▓}{4.4}L=4.4NS2тАЛ тАФ Length of summit curve for SSD (when L>SSDL > SSDL>SSD)

y=ax2y = ax┬▓y=ax2 тАФ Equation of a simple parabolic curve

тЪЩя╕П Working Principle

A summit curve is designed such that the rate of change of grade (rrr) is constant throughout the curve. Since the slope (dy/dxdy/dxdy/dx) of a parabola is a linear function, the second derivative (d2y/dx2d^2y/dx┬▓d2y/dx2) is constant. This constant rate of change ensures that the change in sight distance and the transition between different vertical gradients occur in a predictable and smooth manner.

ЁЯУМ Key Points
  • тЦ╕

    Summit curves are vertical curves with convexity upwards.

  • тЦ╕

    The primary design criteria for summit curves is sight distance.

  • тЦ╕

    A parabola is chosen over a circular curve because it simplifies the calculation of the rate of change of grade and provides superior riding quality.

  • тЦ╕

    The constant rate of change of grade prevents sudden vertical acceleration shifts.

тЬЕ Advantages
  • тЦ╕

    Ease of calculation for levels/offsets.

  • тЦ╕

    Provides constant rate of change of grade.

  • тЦ╕

    Offers better visibility and ride comfort.

тЭМ Disadvantages / Limitations
  • тЦ╕

    Limited visibility at night compared to flat sections.

  • тЦ╕

    Potential for vehicle bouncing if the curve is too sharp (i.e., high NNN value).

ЁЯЫая╕П Applications / Uses
  • тЦ╕

    Highway geometry design.

  • тЦ╕

    Railway vertical alignment.

  • тЦ╕

    Airport runway transitions.

ЁЯУД Additional Information
  • тЦ╕

    Standard IRC (Indian Roads Congress) guidelines specify the use of parabolic curves for all summit curves.

  • тЦ╕

    Circular curves are usually avoided because the change in grade is abrupt at the junction point (PC/PT), leading to discomfort.

ЁЯУК Diagram / Illustration
Summit Curve Profile
Equation: y=ax2+bx+cy = ax^2 + bx + cy=ax2+bx+c
yyy
xxx
тЬЕ

B is correct тАФ The parabolic profile is the ideal form for a summit curve because it maintains a constant rate of change of grade, facilitating a smooth transition and optimal visibility for drivers.

Core Concepts Used
Click any tag to open in AI Tutor
Vertical Alignment Sight Distance (SSD/OSD) Rate of change of grade Geometric Design of Highways
ЁЯТб EXAM TIP

Always remember that summit curves are designed based on sight distance, whereas valley curves are designed based on headlight sight distance and comfort criteria.

Related Questions

CivilTransportation Engineering
The bed block is generally cast with concrete grade
CivilTransportation Engineering
Lead cores are provided in laminated elastomeric bearing is
CivilTransportation Engineering
Bearings are provided in bridges to
CivilTransportation Engineering
Suspension bridges are
CivilTransportation Engineering
A bridge or viaduct carrying a waterway over a valley or other gap is called?

Discussion (0)

Loading discussion...
PrevNext